AK4343VN Datasheet, PDF (39/99 Pages) Asahi Kasei Microsystems – Stereo DAC with HP/RCV/SPK-AMP

[AK4343]
3) EQ
fs: αϯϓϦϯάप೾਺
fc₁: ۃͷप೾਺
fc₂: ྵ఺ͷप೾਺
f: ೖྗ৴߸प೾਺
K: ήΠϯ[dB] (࠷େ+12dB·ͰઃఆͰ͖·͢ɻ)
Ϩδελઃఆ
EQA[15:0] bits =A, EQB[13:0] bits =B, EQC[15:0] bits =C
(MSB=EQA15, EQB13, EQC15; LSB=EQA0, EQB0, EQC0)
1 + 1 / tan (πfc₂/fs)
A = 10^K/20 x
,
1 + 1 / tan (πfc₁/fs)
1 − 1 / tan (πfc₁/fs)
B=
,
1 + 1 / tan (πfc₁/fs)
1 − 1 / tan (πfc₂/fs)
C =10^K/20 x
1 + 1 / tan (πfc₁/fs)
఻ୡؔ਺
ৼ෯
Ґ૬
H(z) =
A + Cz ^−1
1 + Bz ^−1
M(f) =
A² + C² + 2ACcos (2πf/fs)
1 + B² + 2Bcos (2πf/fs)
θ(f) = tan ^−1
(AB−C)sin (2πf/fs)
A + BC + (AB+C)cos (2πf/fs)
[্ࣜʹΑΓࢉग़͞ΕͨϑΟϧλ܎਺Λ࣮਺͔Β2ਐ਺(2ͷิ਺)΁ม͢׵Δखॱ]
X=(্ࣜʹΑΓࢉग़͞Ε࣮ͨ਺ͷϑΟϧλ܎਺) x 2¹³
͜ͷXͷখ਺఺ҎԼΛ࢛ࣺޒೖͨ͠੔਺஋Λ2ਐ਺(2ͷิ਺)ʹมͯ͠׵Լ͍͞ɻ
֤ϑΟϧλ܎਺ઃఆϨδελͷMSB͸ූ߸ϏοτͰ͢ɻ
[ϑΟϧλ܎਺ͷઃఆྫ]
1) FIL1ϒϩοΫ
ྫ: fs=44.1kHz, fc=100HzͷHPFͷ৔߹
F1AS bit = “0”
F1A[13:0] bits = 01 1111 1100 0110
F1B[13:0] bits = 10 0000 0111 0100
2) EQϒϩοΫ
ྫ: fs=44.1kHz, fc₁=300Hz, fc₂=3000Hz, Gain=+8dBͷ৔߹
Gain[dB]
+8dB
fc₁
fc₂
EQA[15:0] bits = 0000 1001 0110 1110
EQB[13:0] bits = 10 0001 0101 1001
EQC[15:0] bits = 1111 1001 1110 1111
Frequency
MS0478-J-02
- 39 -
2010/11